1. Field of the Invention
The invention generally relates to foam covered bendable rod-like articles and associated methods and apparatus. More specifically, the invention relates to bendable closed cell foam covered rod-like articles having specially constructed end portions.
2. Description of the Prior Art
Foam covered bendable wire products are commonly utilized in a variety of fields. For example, such devices are often used as hair curlers, holders for ponytails, and the like. Examples of such devices are described in U.S. Pat. No. 2,542,601 to Van Cleef and U.S. Pat. No. 4,577,647 to Fenster, et al. One problem typically encountered with such articles is that the wire core has a tendency to shift within the foam sheath; thus, the Van Cleef and Fenster, et al. patents describe structures designed to eliminate relative movement between the wire core and foam sheath. The Van Cleef patent describes a hair curler having a wire core with looped ends and a rubber sheath having knobbed ends for containing the looped ends of the wire core, in order to reduce the tendency of the wire core to shift within the rubber sheath. The Fenster, et al. patent seeks to overcome the problem of relative movement between a wire core and foam sheath by providing anchoring means on the core to assist in the core and sheath adjoinment; the anchoring means is described as being either bristle-type members extending from the core or a primer which reacts with the foam material. While such devices represent an improvement over prior art methods, the curlers generally must be manufactured one-at-a-time (and thus are relatively expensive to produce), and relative movement between the core and sheath components tends to occur after the article has been used (i.e., bent and straightened) a number of times.
Foam covered wire products have also in recent times become popular as novelty items, such as novelty jewelry, toys and the like. Such novelty articles are typically produced according to one of two methods. In the first method, a version of which is described in U.S. Pat. No. 5,498,190 to Ganson, a hollow foam tube is produced to have an opening which approximates the size of a wire core which is to be inserted. A wire core is cut to a length which is somewhat shorter than the length of the hollow foam tube, and the ends of the wire core are usually rounded in a conventional manner to eliminate their sharpness. The core is coated with an RF activated adhesive, and the thus-coated wire core is inserted into the hollow foam tube (usually manually) such that the wire core is centered along the foam tube length. As a result, the wire core ends are recessed within the respective corresponding ends of the foam tube. The adhesive is then activated to secure the wire core to the foam tube. The ends of the foam tube can then be treated and a brand applied to the end face of the foam tube to enclose the wire core. While the resulting product has the safety advantages of a recessed wire core which optionally has dull ends, it is often difficult to get a good bond between the wire core and foam tube. As a result, the wire core has a tendency to separate from the foam tube (particularly following the repeated bending and straightening which the article undergoes during use) and it can slide out, thus destroying the product's utility. In addition, the assembly process requires matching predetermined lengths of foam tube with slightly shorter predetermined lengths of wire, inserting and centering the wire in the foam tube, and then bonding the wire to the tube. These assembly steps are laborious and expensive, and cause assembly time to be great.
The second known prior art method of producing such articles is described in U.S. Pat. No. 4,648,414 to Fox, et al. The Fox, et al. patent describes an article having a pliable wire core and a closed cell foam sheath surrounding the core. The article is made by coating the wire core with an adhesive and feeding the coated wire core to an extrusion die, where a foam sheath is extruded about the core. The thus-coated core is then cut into rods of predetermined length, and hot thermoplastic end caps are bonded to the opposite ends of each of the rods. In the resulting article, the foam sheath and the wire core are coextensive in length, with the end caps serving to seal the rod ends and prevent liquid from coming into contact with the wire core. Further, the patent describes that the adhesive serves as a corrosion resistant protective coating for the wire core, as well as securing the wire core to the foam sheath.
While the article and the method of the Fox, et al. patent have been found to be useful in many respects (i.e., an excellent bond is obtained between the core and sheath and the cost of production is relatively lower than that of the first method described above), the wire core extends to the ends of the foam sheath and the ends of the wire core are squared-off rather than being rounded. The end caps are thus advantageously used to shield a user from exposure to the squared off ends of the wire core. However, the end caps add to the manufacturing cost and, once in use, can separate from the article, thereby exposing a user to the wire core and the ends of the wire core to adverse influences such as moisture.